1.Field of the Invention
The present invention relates to zoom lenses, and more particularly to a zoom lens used in a television camera or the like having a small size, a light weight, a large aperture and a large zoom ratio.
2.Related Background Art
Recently, a small and light-weight zoom lens having a large aperture and a wide angle has been demanded more and more. Each of most zoom lenses having a large zoom ratio has a four-lens group system comprising a first lens group having positive refracting power, a second lens group having a negative refracting power, a third lens group having a negative or positive refracting power, and a fourth lens group having a positive refracting power, the first to fourth lens groups being arranged in this order from the object side. Zooming operation is effected by moving the second and third lens groups.
In the conventional zoom lens having this structure, it is proposed to increase the refracting power of each lens group in order to enhance the specifications of the zoom lens as well as to reduce the weight or maintain the light weight. When the refracting power of lens groups each having a simple structure is enhanced, various aberrations increase and the performance of the lens groups is lowered.